In a group of 15,7 have studied Latin, 8 have studied Greek, and 3 have not studied either.How many of these studied both Latin and Greek

A.0 B.3 C.4 D.5

• N(A* n B*)=nU - nA- nB+ n(AnB) wher A* is compliment..ie P(A)*=1-p(A)
  
  3= 15- 8- 7+ X
  
  thus X=3
• 10 years agoHelpfull: Yes(3) No(5)
• 3 have not studied anything so total 12 people know any one.
  
  12 = 8+7-x
  x=3.
  
• 9 years agoHelpfull: Yes(3) No(2)
• 7+8-x=12...........(1)
  as 15-3(who dont study either..)=12
  let x be who study both...
  from (1)
  x=15-12=3...
  
• 9 years agoHelpfull: Yes(0) No(1)
• latin=7
  greek=8
  neither latin nor greek=3
  let those who studied only latin=7-t
  and only greek =8-t
  where t is the no of students who studied both
  so t+7-t+8-t+3=15
  t=3
  
• 7 years agoHelpfull: Yes(0) No(0)